Problem with diacritic, getting data from database java

Question

I have MySQL database, where I have saved data and some words have diacritics.

This is my function how to get data from database.

public List<RowType> getData(String query){

    List<RowType> list = new ArrayList<>();
    try{
        connect();
        Statement statement = connection.createStatement();
        ResultSet resultSet = statement.executeQuery(query);

        while(resultSet.next()){
            StringBuilder str = new StringBuilder();
            for(int i = 1; i <= getCountColumns(resultSet); i++){
                if(i==1) str.append(resultSet.getString(i));
                else str.append("," + resultSet.getString(i));
            }
            list.add(new RowType(str.toString()));
        }
    }
    catch(Exception e){
        System.out.println("Chyba při získavání údajů z databáze.");
        System.out.println(e);
        Console.print("Chyba při získavání údajů z databáze.");
        Console.print(e.toString());
    }
    finally{
        disconnect();
    }
    return list;
}

As parameter i send this query.

List<RowType> list = connection.getData("Select id from countries where name = 'Česko'");

But it doesn´t find anything, because i have diacritic in the query ("Česko"). I try it without diacritic and it works. So don´t you know how to fix it to work with accents too?

Do not concatenate user entered strings into a SQL statement. Use PreparedStatement to prevent SQL syntax errors and SQL Injection attacks. — Andreas
– Andreas, Commented Mar 11, 2019 at 23:03
I used PreparedStatement and it works when i send to query "Cesko" so it find id of "Česko", but when i send to query "Česko" so it find nothing. — Martin
– Martin, Commented Mar 11, 2019 at 23:28

Kevin fu · Accepted Answer · 2019-03-12 02:11:08Z

0

Can you try to add a few more queries before executing your main query? so it will look something like:

connect();
Statement statement = connection.createStatement();

String query2 = "SET NAMES 'utf8'";
statement.execute(query2);

query2 = "SET CHARACTER SET 'utf8'";
statement.execute(query2);

ResultSet resultSet = statement.executeQuery(query);

if the above does not work for you, then maybe there is an issue with your database settings; if that's the case, you can refer to the answer here

answered Mar 12, 2019 at 2:11

Kevin fu

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2 Comments

Martin Over a year ago

Thank you, the link, which you provided, was helpful. I used following syntax and it works. connection = DriverManager.getConnection("jdbc:mysql://localhost/sportdata?characterEncoding=utf-8","root","");

Martin Over a year ago

I added to my connection "characterEncoding=utf-8" and it.

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